Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!decwrl!labrea!rutgers!tut.cis.ohio-state.edu!bloom-beacon!bu-cs!mirror!ima!think!ephraim
From: ephraim@think.COM (Ephraim Vishniac)
Newsgroups: comp.protocols.appletalk
Subject: tweaking NCSA Telnet's ftp performance?
Message-ID: <30734@think.UUCP>
Date: 9 Nov 88 12:47:50 GMT
Sender: news@think.UUCP
Reply-To: ephraim@think.COM (Ephraim Vishniac)
Organization: Thinking Machines Corporation, Cambridge MA, USA
Lines: 35


TMC just bought two Kinetics EtherPort II cards to speed up file
transfer to our Macs because ftp through the Kinetics gateway was too
slow and error-prone. (Slow: < 4K bytes/second.  Error-prone: in a set
of 34 files averaging 3.5M bytes each, two had extra bytes inserted
and had to be retransmitted.)  The EtherPort cards came with NCSA
Telnet 2.1e among other software.

As soon as we got a card installed, I tried some sample transfers to
check performance.  The default settings (mtu = 512, maxseg = 512,
rwin = 512) gave me 4.2KB/S.  Opening the window all the way (rwin =
4096) tripled that figure to 13KB/S.  (This is under system software
6.0.2, without MultiFinder since it seems cripple ftp performance.)
Unfortunately, the manual isn't very informative about the maximum
values for mtu and maxseg in the absence of a Kinetics gateway.

Questions:

1. Is there an NCSA Telnet 2.2e?  I looked around briefly at
   zaphod.ncsa.uiuc.edu, but I only saw 2.2, not 2.2e.

2. What are the actual limits on mtu and maxseg?  Can I expect
   noticably improved performance if I increase them?  What are
   the hazards or drawbacks of larger values?

I'm also interested in any general folk wisdom about tuning ftp, since
I'm new to this.

Thanks in advance,

Ephraim Vishniac					  ephraim@think.com
Thinking Machines Corporation / 245 First Street / Cambridge, MA 02142-1214

     On two occasions I have been asked, "Pray, Mr. Babbage, if you put
     into the machine wrong figures, will the right answers come out?"